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Stubborn service engine light

I have a 2005 Nissan Altima with a SERVICE ENGINE light that refuses to stay off. Initally, upon hooking the car up to my mechanics computer, the code indicated a faulty crankcase sensor. I purchased the sensor and it was installed. I was then told to drive 30 or 40 miles at various speeds, stop and go traffic without shutting off the engine to reset the computer. This was done twice without success. The light remains on . The inspection was due in December and this is becoming very frustrating not to mention illegal to drive these 40 mile circuts. I have even disconnected the battery, reconnected (light off!), and drove ANOTHER 40 miles. The light stayed off while driving but came back on after restarting. 3 times , 2 different mechanics reset the cars computer with theirs. 4 different computers still diagnose a faulty crankcase sensor. The sensor has been replaced twice. Everyone is stumped and I really don’t want to take the car to a dealer. I’d greatly appreciate any suggestions as to what we’re missing.

How about telling us exactly what CEL you are getting? (Look for the letter “P” proceeded by a three digit number)

Why is it illegal to drive with a Service Engine Light? I’d really like to hear your response.

Reset the light by disconnecting the battery as you once did. Drive around for 1/2 hour and if the light stays off, take it in for your inspection…It’s worth a try…

Please post the exact code the scanners come up with…“crankcase sensor” is not a valid code…

Did the fault code say CKP sensor or crankshaft position sensor?

How many miles?
What engine?

Do you have problems starting the car?
Crankshaft position sensor codes often result in hard starting/no starting.

In our state they will allow youto keep driving legally if you can show repairs are in progress.stolen quote "In Illinois, for example, you’ll receive a waiver after failing a second test and providing proof of spending at least $450 on emissions-related repairs."

“the code indicated a faulty crankcase sensor”

None of the codes say directly that a particular part is bad.
It’s a common misconception.
It could be a problem in the wiring or connectors between the sensor and computer.

@missleman … The reason it is illegal for the OP’er to drive I imagine is because their registration is expired. To register the car, it has to pass emissions, and it won’t pass until the CEL problem is resolved. As Barky mentions above, it’s probably the case that the OP’ers state offers some leniency in this situation.

To OP: Your car is telling you there is something wrong. Disconnecting the battery or turning off the light using a code reader won’t work, because your car computer knows what you are trying to do, and tell the emissions tester computer the CEL has recently been reset. That plan isn’t going to work. You’re going to have to figure out why the CEL keeps coming on.

Maybe get a second opinion. It’s unusual to have a crank sensor problem but no drivability or starting issues. The mechanic may not be replacing the sensor correctly, or is using the wrong version of the sensor for your make/model/year. If he’s not using the OEM version, try that. Get it from the dealership parts dept. Also, it may be that the wiring is bad somewhere between the sensor and the ECM, maybe chaffed and shorting out, or the connectors have degraded aren’t isn’t making a good connection. This sensor isn’t rocket science, but the wires must conduct the signal reliably to the ECM or it won’t work right. Consider to ask you mechanic to test and if necessary replace the wire and connector to that sensor. It’s also possible your have a faulty ECM.

Thanks George. I’ve been lucky enough to live in states (except Washington) that did not have an asinine emissions check to pass each year.

Yes missleman, from the point of view of dealing with emissions testing, I’d have to say I agree with you. But from the point of view of needing to breath the air, well, there is some merit to emissions testing I think, at least in urban areas where there’s a lot of car-miles-per-day being driven per square mile. A friend of mine recently moved from San Franciso (where the air is pretty clean due to the constant sea breeze) to downtown LA (where the air tends to stagnate and there’s a lot more people), and he’s complaining now like crazy about the air pollution affecting his eyes and nose. He finds it very objectionable, and is considering leaving downtown LA as soon as possible with an eye to move towards the beach. And this is an area where they do have emissions testing, so you could imaging how his eyes and nose would be feeling if there were no emissions reqt’s at all.

My experience w/Calif emissions testing is mixed. The main problem is that everything is kept so secretive about the testing process. One of my cars is a Toyota Corolla, and emissions testing on it gives me some grief. For some reason I always am ordered by the state to take it for a treadmill test, when most everyone else gets by with the idle test only. The treadmill test costs more and takes more time and there are fewer vendors to choose from, so it’s more difficult to schedule. What’s even more frustrating is that there seems to be absolutely no way for me to find out why my car requires a treadmill test when most everyone else’s doesn’t.

The main reason the Calif emissions testing process is objectionable is that if your car fails, you are put in a bind. The emissions testing place (if you have a treadmill test) will not give you guidance on what the problem is. In fact they are not allowed (by law) to give you any guidance. But you have to fix it in order to register the car. And quickly, or your registration will run out. So you end up stuck between a rock and a hard place. You can try to fix it yourself, say by replacing the O2 sensor, but if it doesn’t pass, you have to pay the testing fee again. And again. And again.

The only way out is to turn your car over to an emission mechanic. If you do that, then, while it might not get fixed ever, once the billing comes to a certain amount ($500 I think), you can register your car. So emissions testing is thought by a lot of drivers – not to have much to do with clean air – but to simply be a way to separate the driver from his $500.

What’s the actual code?

@GeorgeSanJose your car is old. Have you ever considered that may be the reason why your car always goes on the dyno?

Here’s cars me and my family have currently, or recently got rid of, which all had to go on the dyno.

1994 Toyota Tercel
1994 Toyota Celica 1.8
1995 Toyota Corolla 1.8
1997 Mazda Protege 1.5
1998 Mercedes-Benz C230
1999 Mercedes-Benz C280

The reason on the registration notice is always “high emitter profile” or something to that effect.

All cars were excellently maintained. Everything was up to date.
The Toyotas and the Mazda usually had fairly high HCs
The Benzes always passed with flying colors, in all 5 gases. With the exception of the 1999 Benz, the other cars all had a decent amount of miles on them.

I often go to a local “pick your parts” junkyard to scavenge for stuff. There are always plenty of unwrecked cars there which are newer than any of the cars I just mentioned. Perhaps some of them are there because they can’t pass the smog anymore?

So I think the “old” part is the key.

Good comment though @db4690, you are probably right, its just an older car is probably the reason. I’d be ok with that actually, if the state of Calif would just tell me the reason. If it said on the notice “Your car is being singled out for treadmill testing because it is 20 years old.” But there is nothing on the notice like that, nothing saying “high emitter profile” either. It just says I have to take my car to the “Test Only” place (which is what they call the treadmill test) , and I have no option if I want to register my car. I phoned up the DMV and also a gov’t office referred by the DMV (forget the name), and they both said , the DMV said “We don’t know”, and the other place said “We are not allowed to give you that information”. Very helpful.

I’m all for clean air and understand the need for emissions testing, but the state purposely frustrating people by keeping everything secret about this process isn’t a good practice in my opinion. If I want to know why, they should tell me.

One other thing if you’ll allow me to vent a little here. The car being old as the reason would beg the question why my 40 year old Ford truck needs no emissions testing whatever??! I get a complete pass on that 40 year old truck, it never requires an emission test, and the truck probably emits more from the tailpipe in a mile than my 20 year old Toyota emits in 10 miles.

Sigh … I guess some things, we citizens will never be able to understand … lol

George, information about California vehicle emission testing program can be found at the Bureau of Automotive Repair web site.

Question: Why am I being sent to a Test-Only or Gold Shield station? My car has never failed Smog Check.

Answer: Your car was most likely selected by the High Emitter Profile. This means that even though it may never have failed before, it has been identified through a computer-based selection process as a vehicle which is more likely than others to be emitting unhealthy levels of harmful pollutants. Another possibility is that it was selected via a 2 % random selection for program evaluation purposes. In either case, your vehicle has been designated as a Directed Vehicle.

In the past you stated that your car emitted a high hydrocarbon level during testing, I think this is the reason your car has been selected for Star program testing.

@Nevada545 There’s nothing random about going to the test-only station. Like I said earlier, all of my older Toyotas had pretty high HCs. They barely passed. In spite of being very well maintained. The Bureau of Automotive Repair is undoubtedly aware of these patterns. In fact, those Toyotas I mentioned even had those high HCs when they had low miles.

Not random at all, selected would be more accurate.

"…identified through a computer-based selection process as a vehicle which is more likely than others to be emitting unhealthy levels of harmful pollutants."

Nevada, re “high emitter profile”, does it mean Calif determined I need to treadmill test based on my car’s recent year test results (like you say the barely passing HC’s), or that the determination to treadmill test is based on the make/model/year of the car only, because recent test results of other cars of that same make/model/year had higher than acceptable emissions? i.e. that all Toyota Corollas of that vintage get treadmilled?

I’m not losing any sleep over it. It’s frustrating is all I’m saying. I’d just like whoever is responsible for sending me the “treadmill required” notice, to tell me why my car, and not my neighbors. That isn’t asking for too much is it?

db4690 … unlike your experience, in my car’s case, the HC’s were much lower when the car was new and for the first 8 years, after that they started to creep upward. They leveled off about 6 years ago, almost right at the limit. The most recent test, the car only passed by 2 points, don’t recall the exact numbers, but something like 250 is passing, and my car got an HC level of 248. I’m still trying to decide if the problem is the O2 sensor or the cat. I’ll try to remember to bring my test results comparing when the car was new to the most recent test, and post here for opinions. It’s not an emergency as I have 18 more months before I need to re-test. More curious about it than anything else at this point.

Thanks for your comment about the valve clearance, @Nevada_545. I’ll put that on my routine maintenance list.

The number of cars that fail these “tests” is too low. 3-5%, to make any measurable difference in air quality…But it keeps thousands of test stations and repair shops in business…